Much of the world's energy consumption is dedicated to powering internal combustion based vehicles. Most gasoline and diesel car engines are only 20-30% efficient, such that a major portion of the hydrocarbon fuels is wasted, thereby depleting global resources while producing an excessive quantity of pollutants and greenhouse gasses. With hydrocarbon fuels becoming more scare and more expensive it is desirable to obtain more efficient use of those fuels.
Typical fuel injectors may have hydraulically, electromagnetically, or piezoelectrically actuated injector pins. A piezoelectric element is a material that changes dimensions when a voltage is applied across the element. When the voltage is removed, the piezoelectric element returns to its original dimensions. When used as actuators, many piezoelectric elements are stacked together to form larger piezoelectric elements or “piezoelectric stacks” to increase the displacement of the actuator. In a piezoelectrically actuated fuel injector, one or more of these piezoelectric elements or piezoelectric stacks are used to actuate a fuel injector pin for fuel metering into an internal combustion engine.